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RORγt‐Dependent Preferential Induction of IL‐17F by TLR3 Activation in SHR Immune Cells
Author(s) -
Singh Madhu V,
Cicha Michael Z,
Chapleau Mark W,
Abboud François M
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.966.7
Subject(s) - medicine , endocrinology , rar related orphan receptor gamma , immune system , splenocyte , proinflammatory cytokine , orphan receptor , flow cytometry , population , receptor , chemistry , biology , immunology , inflammation , transcription factor , foxp3 , gene , biochemistry , environmental health
We have shown that spontaneously hypertensive rats (SHR) have an abnormally large population of CD161+ immune cells at birth that increases further with age compared with age matched normotensive Wistar Kyoto rats (WKY). We also found in SHR spleens a greater abundance of CD161+CD4+ cells that expressed IL‐17A and IL‐17F cytokines known to be synthesized predominantly by T helper 17 (Th17) lymphocytes that are prohypertensive and anti‐T regulatory cells. Here we further define the phenotype of the proinflammatory Th17 in SHR vs. WKY. When subjected to in vitro programming by T cells receptor activation in the presence of IL‐6 and TGF‐β, SHR splenocytes showed significantly greater induction of IL‐17F than WKY (1.4 fold in WKY vs 4.7 fold in SHR, p< 0.05). In contrast activation of the TLR3/TRIF‐mediated pathway with the TLR3 agonist poly‐IC resulted in a preferentially much greater expression of IL‐17F in SHR (2.9 fold in WKY vs. 27 fold in SHR) compared to the modest increase in IL‐I7A in both WKY and SHR (1.7 fold in WKY vs. 2.2 fold in SHR). We also found that this enhanced IL‐17F expression in SHR is dependent on a master regulator transcription factor (the orphan receptor RORγt) which polarizes immune cells into IL‐17 producing Th17 cells. RORγt RNA expression was significantly greater in SHR than in WKY splenocytes (5.7 fold more RORgt in SHR). Using flow cytometry, we confirmed the greater expression of RORγt in CD4+CD161+ cells of SHR. Furthermore, the pronounced induction of IL‐17F by TLR3 activation was suppressed by digoxin (5μM), a specific inhibitor of RORγt. We conclude that SHR has an abnormally large population of CD4+CD161+ Th17 cells with a markedly enhanced potential for expression of proinflammatory, prohypertensive IL‐17F in response to TLR3 activation, driven by the master regulator transcription factor orphan receptor RORγt. Support or Funding Information National Institutes of Health Program Project Grant to FMA (HL 14388) VA Merit Review Award to MWC (1 I01 BX001414).